Red Bull, no no no no no no no. Coffee isn't great either IMO, anything that fools your body isn't good for it. It also dehydrates you.
I have the same problem BTW, tend to try and get something eaten before riding, then keep topping myself up during. Even very small amounts of 'fast' carbohydrate work for me as long as I stay properly hydrated - the body needs water to metabolise fat into energy, which it can do quickly enough to keep you going providing you give it plenty of hydration.